The present invention relates to a utility model of mannequin, and more particularly to an improved structure of a mobile mannequin. Mannequins having movable joints are known in the art for a variety of purposes such as art study and sporting demonstrations. For example, known mannequins have movable arms, legs, hands and feet. One known type of mannequin includes a trunk ball joint to permit limited motion of a trunk section of the mannequin. However, known trunk ball joints limits movement of the trunk section mannequin, thereby limiting the number of possible positions for the mannequin. Accordingly, the mannequin is prevented from achieving a substantial number of desired poses or motions.